This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. xc2xa7119 from an application for Tension Mask Assembly for Color CRT earlier filed in the Korean Industrial Property Office on Dec. 8, 2000 and there duly assigned Serial No. 2000-74795.
1. Field of the Invention
The present invention relates to a color cathode-ray tube (CRT), and more particularly, to a tension mask assembly for a color cathode-ray tube having a technique for attenuating vibrations of a tension mask due to external impacts.
2. Description of the Background Art
In a typical color cathode-ray tube an electron gun installed in a neck portion of a funnel emits three types of electron beams of red, green and blue colors. These electron beams pass through hundreds of thousands of electron beam passing holes formed in the surface of a shadow mask having a color selection function. The electron beams passing through the electron beam passing holes land at red, green and blue fluorescent materials of a fluorescent film formed on the inner surface of a panel which is coupled to the funnel forming a seal. Thus, the fluorescent materials are excited so that a predetermined image is formed.
In the above color cathode-ray tube, to improve a view angle of a view and prevent distortion of an image, making a flat screen surface has been required. Accordingly, the shadow mask installed inside the color cathode-ray tube and having a color selection function is needed to be made flat.
For this purpose, in an earlier shadow mask of a color cathode-ray tube has a frame including first and second support members installed parallel to each other and first and second elastic members of which end portions are secured to each of the first and second support members. A flat type tension mask having slots with electron beam passing holes formed in strips therein as a plurality of strips are connected by bridges is welded to the first and second support members and while a tension force is applied thereto.
However, in the earlier tension mask assembly for a color cathode-ray tube, the tension mask formed of a thin plate having a thickness of 0.1 through 0.25 mm (millimeters) is welded to the frame by being tensioned. In particular, since only the long side edges thereof are secured to the support members while the short side edges hereof are not secured, the tension mask easily vibrates by small impacts applied from the outside.
Thus, the electron beams emitted from the electron gun do not pass the electron beam passing holes at an accurate amount so that they are not able to accurately land at a predetermined position of the fluorescent material. Accordingly, a howling phenomenon that an image vibrates is generated and resolution of an image is lowered. An exemplar of art is a mask frame assembly reducing vibrations using a damper operation disclosed in Japanese Patent Publication No. 2000-77007 and European Patent Application EP0984482A2 by Suzuki for Color Cathode-ray Tube.
It is therefore an object of the present invention to provide a tension mask assembly for a color cathode-ray tube having a vibration attenuation unit for attenuating vibrations of the tension mask assembly due to external impacts so that a howling phenomenon and lowering of resolution of an image can be prevented.
It is another objective to have tension mask that provides a stable image for a cathode-ray tube.
It is yet another object to have a tension mask that is easy to manufacture.
Accordingly, to achieve the above objectives, there is provided a tension mask assembly for a color cathode-ray tube having a tension mask including a plurality of strips separated a predetermined distance from each other to form slots, a plurality of bridges connecting the strips to section the slots, and a plurality of holes formed in each of short side portions of the tension mask, a frame including first and second support members supporting both long side portions of the tension mask to apply a tension force to the strips of the tension mask, and at least a pair of elastic members supporting the first and second support members, and a plurality of vibration attenuation units coupled to the holes formed at both short side portions of the tension mask to attenuate vibrations of the tension mask.
It is preferred in the present invention that at least one of both end portions of the vibration attenuation units is bent so as not to be separated from each of the holes of both short side portions of the tension mask.
Also, it is preferred in the present invention that the vibration attenuation unit is formed of a material having density greater than that of the tension mask.
Also, it is preferred in the present invention that at least one end portion of the vibration attenuation unit is bent at least two times to encompass an outside edge portion of each of the holes so that the vibration attenuation unit can be secured with respect to the outside edge portion of each of the holes of both short side portions of the tension mask.
Also, it is preferred in the present invention that the vibration attenuation unit has an insertion portion inserted in each of the holes of both side portions of the tension mask to which the vibration attenuation unit is coupled, a connection portion extending from the insertion portion and bent to encompass the outside edge portion of each of the holes, and an extension portion extending from the connection portion and bent toward the insertion portion.
Also, it is preferred in the present invention that the extension portion is further bent toward the outside edge portion of each of the holes while encompassing the outside edge portion.